Ames, Ia. — Republican Tim Pawlenty, who is exploring a 2012 presidential run, opened a campaign event here today by congratulating President Barack Obama on taking out Osama bin Laden.

Pawlenty, the former Minnesota governor, spent far less time criticizing the president in his stump speech than I’ve heard him do in recent appearances. But he didn’t hesitate to raise criticism later, during a question-and-answer session, related to economic issues and jobs.

I asked Pawlenty whether it’s difficult to criticize the president right now, in light of this week’s major military success.

“President Obama should be congratulated for his commitment and decision-making in the capture of bin Laden,” Pawlenty said. “But that’s not the full scope of our foreign policy or our national defense posture and there will still be a robust debate about what he has done so far and what he will do in the future.”

That answer, which didn’t criticize the president, suggests it is tough to do right now. But Pawlenty did eventually sharpen his rhetoric. During the Ames event, he accused Obama of “breaking his promise” to fix health care in a bipartisan fashion and focus on cost containment.

“He broke his promise to Iowa and he broke his promise to America,” Pawlenty said. “He went to Washington, DC, and passed what it is in my view one of the worst pieces of legislation in the modern history of the country. It was one of the most partisan, polarized pieces of legislation in the country. He did not incorporate Republicans or Republican thinking in the result and he did not focus on cost containment.”

Pawlenty also said he does not favor cutting the defense budget. He said he believes some efficiencies can be found, and he anticipates savings as the wars in Iraq and Afghanistan ramp down. But he wouldn’t trim the core defense budget and could even expect increases at the rate of inflation.

“I don’t think given the threats we face and how face they can materialize and how massive the damage can be to the United States, that we can afford to diminish our defense capabilities,” he said.

I suspect that in a week where the 9/11 destruction is playing over and over on the tube, keeping a strong defense will be a prominent theme for most candidates.

I live-tweeted his speech, and will also cover his event tonight. He’ll host a town hall at 6:30 p.m. at the Adel Public Library.